A hypothesis is a statement about one or more variables. This statement may or may not be correct. The validity of this statement is tested on the basis of experiments or observations. There are two types of a hypothesis that are directional and non-directional hypothesis. Directional hypothesis measures the effects of two variables on each other. In other words, it measures the direction of variation of two variables. This effect of one variable on the other variable can be in positive direction or in negative direction. Moreover, non-directional hypothesis does not indicate the kind of effects but only shows the relation between two variables.